The present invention relates to a thermal head printer including a thermal print head carrying linearly arrayed dot print elements to which are applied print signals from shift registers undergoing a clock-controlled shift scan and having a number of addresses corresponding to the number of dot elements, and a dot print signal generating circuit for outputting a dot print signal just when the number of clocks pulses, e.g. as counted by a counter, corresponds to the level, e.g., in digitized form, of each of a series, input signals derived, e.g., by sampling a waveform, the printer being adapted to effect simultaneous one-line dot printing in accordance with the dot print signals stored in the shift registers in response to print command signals.
In a typical arrangement of this type of thermal head printer used for performing dot printing with a high resolving power by, e.g., sampling analog waveforms, the dot print signals are supplied at high velocity to shift registers incorporated into the thermal print head, and the dot print elements may in principle be operated at a corresponding velocity.
Actually, however, the printing speed is so restricted that the dot print elements are exothermically responsive to a heat-sensitive chart.